Solar Load and System Calculator

Site

Sun hours set the array size. The coldest temperature sets the maximum string voltage, and the hottest sets the minimum.

Country City

Latitude (°) Longitude (°)

Site values

Sun hours, yearly (h/day) Sun hours, worst month (h/day) Lowest temperature (°C) Hot-month high (°C)

Electrical code and grid

AC supply AC voltage (V)

System type

Pick how the system connects to the grid.

Off-grid settings

Days of autonomy Size array for

Hybrid settings

Use from solar (%) Battery covers

Use after sunset (%) Backup load (W) Backup time (h)

Grid-tie settings

Use from solar (%) DC/AC ratio

Roof and margin

Design margin (%) Roof limit (panels, 0 = none)

Loads

Add each appliance for a detailed audit, or enter the kWh from your electric bill for a quick estimate.

Appliance

Appliance	Watts	Qty	Hours/day	Start surge ×	Wh/day

Running at once (% of watts)

Use the watts on the appliance label. For fridges and aircons, hours/day means hours the compressor runs, about half the hours it is switched on. Start surge is how many times its running watts a motor draws for a second at start-up.

Monthly use (kWh) Peak load (W, blank = estimate) Largest motor (W)

Equipment

Start with a preset, then type in values from your datasheets.

Solar panel

Panel

Rated power (Wp) Voc (V)

Vmp (V) Isc (A) Imp (A) Max series fuse (A)

Voc temp. coeff. (%/°C) Pmax temp. coeff. (%/°C)

Battery

Chemistry System voltage Battery module

Module voltage (V) Module capacity (Ah) Usable depth (% DoD) Round trip (%)

Inverter

Surge capability (× rating, 5 s)

Inverter PV input limits

Use typical values for this size

Max DC input (V) Max current per MPPT (A) MPPT low (V) MPPT high (V) MPPT inputs

Losses

Inverter eff. (%) Dirt loss (%) DC wiring loss (%) Mismatch loss (%)

Cable runs, one way

Panels to inverter (m) Combiner to inverter (m) Battery to inverter (m) Inverter to panel board (m)

Max drop, PV (%) Max drop, battery (%) Max drop, AC (%)

Solar Load and System CalculatorSolar Calculator

Site

Site values

Electrical code and grid

System type

Off-grid settings

Hybrid settings

Grid-tie settings

Roof and margin

Loads

Equipment

Solar panel

Battery

Inverter

Inverter PV input limits

Losses

Cable runs, one way

Results

What do you want to do?

Reference guide

Edit appliance